update pictures

Author: Clara Raubertas

sites/en/intro-to-rails/pictures.step

@@ -30,10 +30,12 @@ end
   end
   step do
     message 'Open `app/uploaders/picture_uploader.rb:`'
-    message 'Add the code
-``` ruby
+    message 'Add the code'
+message ```ruby
 include Cloudinary::CarrierWave
 ```'
+message 'under the line `class PictureUploader < CarrierWave::Uploader::Base`'
+
 explanation do
 message "This line tells the uploader to include some code from the `cloudinary` gem which enables CarrierWave to use Cloudinary as a storage system."
 end